Run the integration tests in a single process to detect usages of static state

[keyboardDrummer]

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The language server runs compilation multiple times using a single process. To test that such repeated executions in a single process work well together, it would be good to also do this while running integration tests.

Related issue: https://github.com/dafny-lang/dafny/issues/2945

Issue to help with CI problem: https://github.com/microsoft/vstest/issues/4376#issuecomment-1504905609

[keyboardDrummer]

Partially completed with https://github.com/dafny-lang/dafny/pull/3715